Head injury and dementia
Published on 13/5/2020
Dr Chris Perkins highlights the increased risk of dementia associated with head injuries.
Rugby players and coaches are now taking concussion seriously since a number of old All Blacks have been diagnosed with dementia. Head injury has long been known to be a risk factor for progressive cognitive impairment. It may reduce “cognitive reserve”, meaning there is less total working brain, so that when through ageing, Alzheimer’s or vascular problems the brain gets further damaged, there is less tissue available to resist the disease process. There are many people in New Zealand with some degree of head injury (36, 000 cases per year according to research published in 2012), all ageing and potentially developing dementia. An interesting ACC paper (2012) summarises the research on ageing and traumatic brain injury. Dementia is one known outcome. https://www.acc.co.nz/assets/research/tbi-review-ageing.pdf
On the other hand, older people often have head injuries – from falls and other accidents. The frailer, older brain is more vulnerable to injury and recovery is slower. For example, if there is shrinkage of the brain, there is more space for blood to accumulate after a hit on the head and an increased likelihood of subdural haematoma. ACC have published a document, Standing up to falls: Your Guideline to preventing falls and protecting your independence and have a new website www.livestronger.org.nz. People with dementia are highly likely to fall for a variety of reasons, such as visio-spatial perception changes, muscle wasting, poor balance, medication, incontinence, the progression of the condition and so on. If a fall causes head injury there is further cognitive impairment.
Why am I writing about this?
First, it seems important that people (like rugby players) know that avoiding head injury will reduce their chances of developing dementia. Those who already have a head injury, could be encouraged to do everything possible to mitigate its effects. This would mean following a lifestyle to lessen dementia risk: social and intellectual activity, treatment of diabetes, hypertension, obesity and high lipids, increasing exercise and avoiding smoking and excess alcohol. Depending on the seriousness of the head injury much of this could be difficult to carry out, but some of it will be possible.
For older people, reducing fall risk has got to be a high priority, and ACC is publishing the above useful guidelines on how to do this.
Finally, head injury, intellectual disability and long term mental illness all predispose to dementia. Too often we work in silos, trying to put people in one box (or silo) or another when they need assistance from several systems We have to work together to ensure that each individual with their complex needs gets the help they deserve, to reduce their risk of dementia and to provide personalised care should they need it.
Chronic traumatic encephalopathy in US Football players. Link
The largest study yet of dead former NFL players found that over 99% had permanent brain damage: Link
About the author
After working in General Practice Chris trained in psychiatry, specialising in mental health for older people. She has worked in this area for nearly 30 years with a particular interest in dementia. She is the author of books on dementia (The New Zealand Dementia Guide (2004), revised 2006, Dementia, What you need to know (2013), Random House / Penguin).